Three years ago, Google tried to tackle the problem of email overload by introducing Gmail's Priority Inbox, a repository for messages deemed by Google's algorithms to be important.

At the time, Google pitched email segregation as a way to make office workers more productive. By automatically filtering meaningful messages from the rest, Gmail has the potential to save an average of 46 minutes per week that would otherwise be spent dealing with email, it said.

Perhaps businesses realized savings as a result or perhaps workers just frittered away recovered time on Facebook. Either way, email still seems to be productivity issue. McKinsey Global Institute in 2012 found that knowledge workers spend an average of 28% of their workweek reading and replying to email.

So Google is ready to take another stab at dealing with information overload, a problem that it may be exacerbating by making Google Drive files and Calendar entries accessible through Gmail's search box.

On Wednesday, the company introduced a new Gmail inbox design that segregates messages even more than its Priority Inbox. The revised Gmail now includes no less than five inboxes, accessible from a horizontal line of tabs atop the inbox message list.

Think of it as an interface designed to divide-and-conquer. It won't actually reduce the volume of messages you receive, but it will make incoming messages easier to ignore by separating them into distinct categories and hiding them behind tabs. Out of sight, out of mind.

The new tabs are: Primary, for the messages you care about; Social, for those annoying social notifications; Promotions, for messages of obviously commercial nature that don't quite qualify as spam; Updates, for the messages you get after taking advantage of a promotion or other notifications, receipts and the like; and Forums, for those discussions from which you can't be bothered to unsubscribe.

The new Gmail can be seen not only in desktop browsers but also in Gmail for Android 4.0+ and Gmail for iPhone and iPad.

Those who dislike such changes-- and there are always people who dislike design changes -- can rest assured the tab-oriented interface is optional. Gmail users can configure their inboxes with or without tabs, and can revert to the Classic view if they prefer.

Much of what the new Gmail accomplishes could be done with Gmail filters. But Google's goal is to make email management easier for those who don't usually bother with the knobs and dials that customize applications. Filters also don't have an interface component, even though they can affect message presentation.

Unlike filters, the new Gmail Inbox can learn, in a manner of speaking. It adapts the way Gmail's spam filter and Priority Inbox do. For example, if you drag a message to the Promotions tab because it was inappropriately routed to another tab, the Gmail system is designed to learn from your example.

Gmail's new Inbox will be rolled out gradually. To see if it has been activated, check Gmail's Settings menu (the gear icon on the top right) for the "Configure inbox" option. Another sign of the new Inbox is the appearance of a Categories menu and disclosure triangle in the left-hand menu pane, just below the Trash menu item. The Categories menu will collapse the five tabs into a unified view, adding colored category labels to the vertical message list.